Consumers’ concepts of materials

User needs and wants dictate the way in which products are designed, produced, used and disposed of. Western society in particular has become very consumer driven and the waste resulting from such activity has the potential to be disastrous. The creation of emotional attachment with possessions is one way of approaching sustainable consumer-product relationships. The aim of this research was to gain a deeper understanding of the interaction and emotional attachment that consumers have and develop with their products. It outlines literature relating to consumer emotion and experience in relation to products, and how pleasurable product user relationships can be prolonged. It is evident from the literature that the roles of materials in the emotional attachment consumers have with products needed to be further explored. A study was conducted to determine consumers. concepts of six materials currently used in product design. This involved participants being given a Concept Prompt Probe with textual prompts to assist in discussion about the materials in question. The discussions between the 15 participant groups of two people, one male and one female, were then transcribed and coded ready for analysis. The study findings demonstrate consumers. concepts of the six materials. The findings show both physical and emotional consumer concepts of the materials. It is, however, the interaction of these concepts that is the most significant finding of this research. Each material concept is not only judged emotionally by consumers in its own right but in relation to other concepts as well. The interaction of the consumers. concepts of materials can considerably effect the emotional judgement made about the material and the appropriateness of its application. This research makes a significant contribution to knowledge regarding the effect materials have on the consumers by identifying how materials can prompt emotional judgements and thereby alter the product user experience.

A review of simulation models for railway systems

With the advances in computer hardware and software development techniques in the past 25 years, digital computer simulation of train movement and traction systems has been widely adopted as a standard computer-aided engineering tool [1] during the design and development stages of existing and new railway systems. Simulators of different approaches and scales are used extensively to investigate various kinds of system studies. Simulation is now proven to be the cheapest means to carry out performance predication and system behaviour characterisation. When computers were first used to study railway systems, they were mainly employed to perform repetitive but time-consuming computational tasks, such as matrix manipulations for power network solution and exhaustive searches for optimal braking trajectories. With only simple high-level programming languages available at the time, full advantage of the computing hardware could not be taken. Hence, structured simulations of the whole railway system were not very common. Most applications focused on isolated parts of the railway system. It is more appropriate to regard those applications as primarily mechanised calculations rather than simulations. However, a railway system consists of a number of subsystems, such as train movement, power supply and traction drives, which inevitably contains many complexities and diversities. These subsystems interact frequently with each other while the trains are moving; and they have their special features in different railway systems. To further complicate the simulation requirements, constraints like track geometry, speed restrictions and friction have to be considered, not to mention possible non-linearities and uncertainties in the system. In order to provide a comprehensive and accurate account of system behaviour through simulation, a large amount of data has to be organised systematically to ensure easy access and efficient representation; the interactions and relationships among the subsystems should be defined explicitly. These requirements call for sophisticated and effective simulation models for each component of the system. The software development techniques available nowadays allow the evolution of such simulation models. Not only can the applicability of the simulators be largely enhanced by advanced software design, maintainability and modularity for easy understanding and further development, and portability for various hardware platforms are also encouraged. The objective of this paper is to review the development of a number of approaches to simulation models. Attention is, in particular, given to models for train movement, power supply systems and traction drives. These models have been successfully used to enable various ‘what-if’ issues to be resolved effectively in a wide range of applications, such as speed profiles, energy consumption, run times etc.

An event-based traffic flow model for traffic control at railway junctions

This paper introduces an event-based traffic model for railway systems adopting fixed-block signalling schemes. In this model, the events of trains' arrival at and departure from signalling blocks constitute the states of the traffic flow. A state transition is equivalent to the progress of the trains by one signalling block and it is realised by referring to past and present states, as well as a number of pre-calculated look-up tables of run-times in the signalling block under various signalling conditions. Simulation results are compared with those from a time-based multi-train simulator to study the improvement of processing time and accuracy.

The application of profluorescent nitroxides to detect reactive oxygen species derived from combustion-generated particulate matter: Cigarette smoke – a case study

Reactive oxygen species (ROS) and related free radicals are considered to be key factors underpinning the various adverse health effects associated with exposure to ambient particulate matter. Therefore, measurement of ROS is a crucial factor for assessing the potential toxicity of particles. In this work, a novel profluorescent nitroxide, BPEAnit, was investigated as a probe for detecting particle-derived ROS. BPEAnit has a very low fluorescence emission due to inherent quenching by the nitroxide group, but upon radical trapping or redox activity, a strong fluorescence is observed. BPEAnit was tested for detection of ROS present in mainstream and sidestream cigarette smoke. In the case of mainstream cigarette smoke, there was a linear increase in fluorescence intensity with an increasing number of cigarette puffs, equivalent to an average of 101 nmol ROS per cigarette based on the number of moles of the probe reacted. Sidestream cigarette smoke sampled from an environmental chamber exposed BPEAnit to much lower concentrations of particles, but still resulted in a clearly detectible increase in fluorescence intensity with sampling time. It was calculated that the amount of ROS was equivalent to 50 ± 2 nmol per mg of particulate matter; however, this value decreased with ageing of the particles in the chamber. Overall, BPEAnit was shown to provide a sensitive response related to the oxidative capacity of the particulate matter. These findings present a good basis for employing the new BPEAnit probe for the investigation of particle-related ROS generated from cigarette smoke as well as from other combustion sources.

Theoretical analysis of the motion and evaporation of exhaled respiratory droplets of mixed composition

The dynamics of droplets exhaled from the respiratory system during coughing or talking is addressed. A mathematical model is presented accounting for the motion of a droplet in conjunction with its evaporation. Droplet evaporation and motion are accounted for under two scenarios: 1) A well mixed droplet and 2) A droplet with inner composition variation. A multiple shells model was implemented to account for internal mass and heat transfer and for concentration and temperature gradients inside the droplet. The trajectories of the droplets are computed for a range of conditions and the spatial distribution and residence times of such droplets are evaluated.

Exposure to particle number, surface area and PM concentrations in pizzerias

The aim of this work was to quantify exposure to particles emitted by wood-fired ovens in pizzerias. Overall, 15 microenvironments were chosen and analyzed in a 14-month experimental campaign. Particle number concentration and distribution were measured simultaneously using a Condensation Particle Counter (CPC), a Scanning Mobility Particle Sizer (SMPS), an Aerodynamic Particle Sizer (APS). The surface area and mass distributions and concentrations, as well as the estimation of lung deposition surface area and PM1 were evaluated using the SMPS-APS system with dosimetric models, by taking into account the presence of aggregates on the basis of the Idealized Aggregate (IA) theory. The fraction of inhaled particles deposited in the respiratory system and different fractions of particulate matter were also measured by means of a Nanoparticle Surface Area Monitor (NSAM) and a photometer (DustTrak DRX), respectively. In this way, supplementary data were obtained during the monitoring of trends inside the pizzerias. We found that surface area and PM1 particle concentrations in pizzerias can be very high, especially when compared to other critical microenvironments, such as the transport hubs. During pizza cooking under normal ventilation conditions, concentrations were found up to 74, 70 and 23 times higher than background levels for number, surface area and PM1, respectively. A key parameter is the oven shape factor, defined as the ratio between the size of the face opening in respect

Adverse health effects to air pollution and guidelines to prevent them

This is the first in a series of four articles which will explore different aspects of air pollution, its impact on health and challenges in defining the boundaries between impact and nonimpact on health. Hardly a new topic one might say. Indeed, it’s been an issue for centuries, millennia even! For example, Pliny the Elder (AD 23-79), a Roman officer and author of the ‘Natural History’ recommended that: “…quarry slaves from asbestos mines not be purchased because they die young”, and suggested: “…the use of a respirator, made of transparent bladder skin, to protect workers from asbestos dust.” Closer to modern times, a Danish Proverb states: "Fresh air impoverishes the doctor". While none of these statements are an air quality guideline in a modern sense, they do illustrate that, for a very long time, we have known that there is a link between air quality and health, and that some measures were taken to reduce the impact of the exposure to the pollutants. Obviously, we are much more sophisticated now!

Application of chemometrics to analysis of soil pollutants

This overview focuses on the application of chemometrics techniques for the investigation of soils contaminated by polycyclic aromatic hydrocarbons (PAHs) and metals because these two important and very diverse groups of pollutants are ubiquitous in soils. The salient features of various studies carried out in the micro- and recreational environments of humans, are highlighted in the context of the various multivariate statistical techniques available across discipline boundaries that have been effectively used in soil studies. Particular attention is paid to techniques employed in the geosciences that may be effectively utilized for environmental soil studies; classical multivariate approaches that may be used in isolation or as complementary methods to these are also discussed. Chemometrics techniques widely applied in atmospheric studies for identifying sources of pollutants or for determining the importance of contaminant source contributions to a particular site, have seen little use in soil studies, but may be effectively employed in such investigations. Suitable programs are also available for suggesting mitigating measures in cases of soil contamination, and these are also considered. Specific techniques reviewed include pattern recognition techniques such as Principal Components Analysis (PCA), Fuzzy Clustering (FC) and Cluster Analysis (CA); geostatistical tools include variograms, Geographical Information Systems (GIS), contour mapping and kriging; source identification and contribution estimation methods reviewed include Positive Matrix Factorisation (PMF), and Principal Component Analysis on Absolute Principal Component Scores (PCA/APCS). Mitigating measures to limit or eliminate pollutant sources may be suggested through the use of ranking analysis and multi criteria decision making methods (MCDM). These methods are mainly represented in this review by studies employing the Preference Ranking Organisation Method for Enrichment Evaluation (PROMETHEE) and its associated graphic output, Geometrical Analysis for Interactive Aid (GAIA).

Mobile communication in power distribution application

This paper investigates how to interface the wireless application protocol (WAP) architecture to the SCADA system running distributed network protocol (DNP) in a power process plant. DNP is a well-developed protocol to be applied in the supervisory control and data acquisition (SCADA) system but the system control centre and remote terminal units (RTUs) are presently connected through a local area network. The conditions in a process plant are harsh and the site is remote. Resources for data communication are difficult to obtain under these conditions, thus, a wireless channel communication through a mobile phone is practical and efficient in a process plant environment. The mobile communication industries and the public have a strong interest in the WAP technology application in mobile phone networks and the WAP application programming interface (API) in power industry applications is one area that requires extensive investigation.

Excess length of stay due to central line–associated bloodstream infection in intensive care units in Argentina, Brazil, and Mexico

Objective.To estimate the excess length of stay in an intensive care unit (ICU) due to a central line–associated bloodstream infection (CLABSI), using a multistate model that accounts for the timing of infection. Design.A cohort of 3,560 patients followed up for 36,806 days in ICUs. Setting.Eleven ICUs in 3 Latin American countries: Argentina, Brazil, and Mexico. Patients.All patients admitted to the ICU during a defined time period with a central line in place for more than 24 hours. Results.The average excess length of stay due to a CLABSI increased in 10 of 11 ICUs and varied from −1.23 days to 4.69 days. A reduction in length of stay in Mexico was probably caused by an increased risk of death due to CLABSI, leading to shorter times to death. Adjusting for patient age and Average Severity of Illness Score tended to increase the estimated excess length of stays due to CLABSI. Conclusions.CLABSIs are associated with an excess length of ICU stay. The average excess length of stay varies between ICUs, most likely because of the case‐mix of admissions and differences in the ways that hospitals deal with infections.

Methacrylate-functionalized oligomers based on lactide, E-caprolactone and trimethylene carbonate for application in stereo-lithography

Photo-curable biodegradable macromers were prepared by ring opening polymerization of D,L-lactide (DLLA), (similar to)-caprolactone (CL) and 1,3-trimethylene carbonate (TMC) in the presence of glycerol or sorbitol as initiator and stannous octoate as catalyst, and subsequent methacrylation of the terminal hydroxyl groups. These methacrylated macromers, ranging in molecular weight from approximately 700 to 6000 g/mol, were cross-linked using ultraviolet (UV) light to form biodegradable networks. Homogeneous networks with high gel contents were prepared. One of the resins based on PTMC was used to prepare three-dimensional structures by stereo-lithography using a commercially available apparatus.

Panel studies of new venture creation : a review and suggestions for future research

We review all journal articles based on “PSED-type” research, i.e., longitudinal, empirical studies of large probability samples of on-going, business start-up efforts. We conclude that the research stream has yielded interesting findings; sometimes by confirming prior research with a less bias-prone methodology and at other times by challenging whether prior conclusions are valid for the early stages of venture development. Most importantly, the research has addressed new, process-related research questions that prior research has shunned or been unable to study in a rigorous manner. The research has revealed an enormous and fascinating variability in new venture creation that also makes it challenging to arrive at broadly valid generalizations. An analysis of the findings across studies as well as an examination of those studies that have been relatively more successful at explaining outcomes give good guidance regarding what is required in order to achieve strong and credible results. We compile and present such advice to users of existing data sets and designers of new projects in the following areas: Statistically representative and/or theoretically relevant sampling; Level of analysis issues; Dealing with process heterogeneity; Dealing with other heterogeneity issues, and Choice and interpretation of dependent variables.

Methacrylate-functionalized oligomers based on lactide, ε- caprolactone and trimethylene carbonate for application in stereo-lithography

Photo-curable biodegradable macromers were prepared by ring opening polymerization of D,L-lactide (DLLA), ε-caprolactone (CL) and 1,3-trimethylene carbonate (TMC) in the presence of glycerol or sorbitol as initiator and stannous octoate as catalyst, and subsequent methacrylation of the terminal hydroxyl groups. These methacrylated macromers, ranging in molecular weight from approximately 700 to 6000 g/mol, were cross-linked using ultraviolet (UV) light to form biodegradable networks. Homogeneous networks with high gel contents were prepared. One of the resins based on PTMC was used to prepare three-dimensional structures by stereo-lithography using a commercially available apparatus.

The urban littoral frontier : land reclamation in the history of human settlements

The urban waterfront may be regarded as the littoral frontier of human settlement. Typically, over the years, it advances, sometimes retreats, where terrestrial and aquatic processes interact and frequently contest this margin of occupation. Because most towns and cities are sited beside water bodies, many of these urban centers on or close to the sea, their physical expansion is constrained by the existence of aquatic areas in one or more directions from the core. It is usually much easier for new urban development to occur along or inland from the waterfront. Where other physical constraints, such as rugged hills or mountains, make expansion difficult or expensive, building at greater densities or construction on steep slopes is a common response. This kind of development, though technically feasible, is usually more expensive than construction on level or gently sloping land, however. Moreover, there are many reasons for developing along the shore or riverfront in preference to using sites further inland. The high cost of developing existing dry land that presents serious construction difficulties is one reason for creating new land from adjacent areas that are permanently or periodically under water. Another reason is the relatively high value of artificially created land close to the urban centre when compared with the value of existing developable space at a greater distance inland. The creation of space for development is not the only motivation for urban expansion into aquatic areas. Commonly, urban places on the margins of the sea, estuaries, rivers or great lakes are, or were once, ports where shipping played an important role in the economy. The demand for deep waterfronts to allow ships to berth and for adjacent space to accommodate various port facilities has encouraged the advance of the urban land area across marginal shallows in ports around the world. The space and locational demands of port related industry and commerce, too, have contributed to this process. Often closely related to these developments is the generation of waste, including domestic refuse, unwanted industrial by-products, site formation and demolition debris and harbor dredgings. From ancient times, the foreshore has been used as a disposal area for waste from nearby settlements, a practice that continues on a huge scale today. Land formed in this way has long been used for urban development, despite problems that can arise from the nature of the dumped material and the way in which it is deposited. Disposal of waste material is a major factor in the creation of new urban land. Pollution of the foreshore and other water margin wetlands in this way encouraged the idea that the reclamation of these areas may be desirable on public health grounds. With reference to examples from various parts of the world, the historical development of the urban littoral frontier and its effects on the morphology and character of towns and cities are illustrated and discussed. The threat of rising sea levels and the heritage value of many waterfront areas are other considerations that are addressed.

The nature of pedagogic teacher-student interactions : a phenomenographic study

Globally, teaching has become more complex and more challenging over recent years, with new and increased demands being placed on teachers by students, their families, governments and wider society. Teachers work with more diverse communities in times characterised by volatility, uncertainty and moral ambiguity. Societal, political, economic and cultural shifts have transformed the contexts in which teachers work and have redefined the ways in which teachers interact with students. This qualitative study uses phenomenographic methods to explore the nature of pedagogic teacherstudent interactions. The data analysis reveals five qualitatively different ways in which teachers experience pedagogic engagements with students. The resultant categories of description ranged from information providing, with teachers viewed as transmitters of a body of knowledge through to mentoring in which teachers were perceived as significant others in the lives of students with their influence extending beyond the walls of the classroom and beyond the years of schooling. The paper concludes by arguing that if teachers are to prepare students for the challenges and opportunities in changing times, teacher education programs need to consider ways to facilitate the development of mentoring capacities in new teachers.